Leukotriene is a metabolite of arachidonic acid, and is well known as an inflammatory factor that is deeply involved in causing inflammation, edema, and secretion of mucus and the like. A well-known leukotriene inhibitor developed so far is zileuton ((±)-1-(1-(benzo[b]thiophen-2-yl)ethyl)-1-hydroxyurea).
Zileuton is a mixture of stereoisomers: (R)-1-(1-(benzo[b]thiopen-2-yl)ethyl)-1-hydroxyure and (S)-1-(1-(benzo[b]thiophen-2-yl)ethyl)-1-hydroxyurea. It has been approved as an oral drug for treatment of asthma, and is known to be administrable twice a day. Clinical trials have shown that zileuton exhibits an effective anti-inflammatory pharmaceutical effect against inflammation reaction of asthma.
Clinical trials have revealed that oral administration of zileuton alleviates atopic dermatitis symptoms. However, zileuton is not being widely used despite its excellent anti-inflammatory effects due to toxicity of the compound.
Zileuton has significant hepatotoxicity, and thus an oral administration of zileuton should be accompanied by monitoring of liver functions of the patient.